SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6955584c179385a71830e0f9297e6fef2bef583aa179d57b89d48decea698609' 
  AND token = '49+dQNYARW4SjPjSCCnHSV2LNWNjzCXA3nrdztsxdjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}